1. Technical Field
The present invention relates to a roller lifter.
2. Related Art
Japanese Patent Application Publication No. JP-A-2014-1706 discloses a roller lifter adapted to be incorporated in internal combustion engines of automotive vehicles. The roller lifter includes a roller brought into contact with a cam, a support pin rotatably supporting the roller and a pair of supports having holes through which both ends of the support pin extend, respectively. The ends of the support pin are swaged thereby to be fixed in the respective holes of the supports. The supports are provided integrally on a cylindrical lifter body. The cam is in abutment against the roller, so that movement of the cam is transmitted to a lifter body with the result that the lifter body is reciprocable in an up-down direction in a cylinder head. The lifter body has an outer periphery serving as a sliding surface which slides on an inner periphery of the cylinder head. Accordingly, the outer periphery of the lifter body requires a strict dimensional accuracy in order to be slidable without backlash in the cylinder head.
In the above-described conventional roller lifter, when both ends of the support pin are swaged thereby to be fixed to the respective supports, there is a possibility that both supports would fall inward so that the supports come close to each other. If both supports fall inward, there is a possibility that the outer periphery of the lifter body would be deformed and the dimensional accuracy of the lifter body cannot be maintained at a proper value.
On the other hand, for example, when both supports are separated from the lifter body so that the cylindrical portion constituting the outer periphery of the lifter body is independent of the supports, the cylindrical portion can be avoided from being influenced by the swaging of the support pin, so that the outer periphery of the cylindrical portion of the lifter body can be maintained at a proper value of dimensional accuracy.
In the aforementioned case, however, the supports need to be connected to the cylindrical portion after the support pin has been swaged. Accordingly, the outer periphery of the cylindrical portion has a possibility of suffering some deformation under the influence of processing during connection. Furthermore, the productivity is possibly reduced when the connecting requires much time.